From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 39B4215C8B for ; Mon, 5 Dec 2022 19:40:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AD5BFC433D6; Mon, 5 Dec 2022 19:40:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1670269251; bh=iDf9UjoRA3CABvNpb5Um878zm5pqaznnxUWABnYAgTE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=y9uxKfyarwsdXoKHnVTL6kclfc5NIjDYuoA4BOtwEhxDO+PN06m4dB9FtCOt8c6K5 88xfQktqf3mcHN/eRqjwnX0Jb9ai4ntQyu+EW3QW0QZ9ALVnrxlFf6GoizA2iHEtaw j5MduMBDIyAoU4VTxqf5B+WTosfvH30RPQTYPFKM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+43475bf3cfbd6e41f5b7@syzkaller.appspotmail.com, Lin Ma , "David S. Miller" , Sasha Levin Subject: [PATCH 5.4 020/153] nfc/nci: fix race with opening and closing Date: Mon, 5 Dec 2022 20:09:04 +0100 Message-Id: <20221205190809.323749683@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221205190808.733996403@linuxfoundation.org> References: <20221205190808.733996403@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Lin Ma [ Upstream commit 0ad6bded175e829c2ca261529c9dce39a32a042d ] Previously we leverage NCI_UNREG and the lock inside nci_close_device to prevent the race condition between opening a device and closing a device. However, it still has problem because a failed opening command will erase the NCI_UNREG flag and allow another opening command to bypass the status checking. This fix corrects that by making sure the NCI_UNREG is held. Reported-by: syzbot+43475bf3cfbd6e41f5b7@syzkaller.appspotmail.com Fixes: 48b71a9e66c2 ("NFC: add NCI_UNREG flag to eliminate the race") Signed-off-by: Lin Ma Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/nfc/nci/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c index b2e922fcc70d..57849baf9294 100644 --- a/net/nfc/nci/core.c +++ b/net/nfc/nci/core.c @@ -530,7 +530,7 @@ static int nci_open_device(struct nci_dev *ndev) skb_queue_purge(&ndev->tx_q); ndev->ops->close(ndev); - ndev->flags = 0; + ndev->flags &= BIT(NCI_UNREG); } done: -- 2.35.1